I doubt my religion constantly, everyone does. No matter what you believe, you are going to hear and see things that make you consider other beliefs over your own. Some people receive answers that eliminate those doubts, others do not and decide to abandon their religion. The important thing is to constantly seek the truth and don't be afraid to ask questions.
I grew up in a judgmental church. They told me there was a right way and a wrong way and that being homosexual was wrong. My homosexual friend wasn’t aloud in the church so in protest I waited outside with him and never went back to that church. I tried other churches but eventually switched my religion to Buddhism. I still have friends that are Christian and they constantly ask me of what I think I believe is right and when I say yes I begin to doubt myself because these people have known me since I was a child.